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health-related problems

Eating right for your brain

Although I’m a cognitive psychologist and consequently think that memory and cognition is mostly about your mastery of effective strategies, when it comes to age-related cognitive decline, I’m a big believer in the importance of diet and exercise. But while we know these things can play an important role in why some people develop cognitive impairment and even dementia as they age, and others don’t, we don’t yet know with any great certainty exactly what exercise programs would be the best use of our time, and what diet would have the most benefit.

The role of diet in fighting age-related cognitive decline is quite complex. Many older people have inadequate diets, partly no doubt because of the shrinking in appetite and perhaps the dulling of taste and smell. It seems to me, for example (and this is purely a casual observation), that sweet foods tend to be appreciated more by the elderly, while other flavors are less able to be appreciated. The problem with the shrinking appetite is that it becomes even more vital, if the quantity of food is much reduced, that the nutritional quality is good. The less you eat, the less you can afford to eat “empty calories”. Everything must count.

Other factors concern the need to fight declining physical health. Cardiovascular problems, cholesterol problems, blood pressure problems, inflammation — all these have been implicated in contributing to cognitive decline. Therefore any diet that helps you fight these problems is also helping you fight cognitive decline.

A recent Swedish study tackled the inflammation problem. The study, involving 44 overweight people aged 50-75, found that after four weeks eating foods presumed to reduce low-grade inflammation, bad (LDL) cholesterol was reduced by 33%, blood triglycerides by 14%, blood pressure by 8% and a risk marker for blood clots by 26%. Memory and cognitive function was also improved (but no details on that were reported, and at present it appears only a press release is available — no academic paper).

The diet was high in antioxidants, low-GI foods (i.e. slow release carbohydrates), omega fatty acids, wholegrain products, probiotics and viscous dietary fibre. Examples of foods eaten were oily fish, barley, soy protein, blueberries, almonds, cinnamon, vinegar and a certain type of wholegrain bread. Some of the products are not yet available in the shops, but were developed specifically for the study.

Another study, involving 712 New Yorkers, found that those who most closely followed a Mediterranean-like diet over a six-year period, were 36% less likely to have brain infarcts compared to those who were least following the diet. Such a diet has also been associated with a lower risk of Alzheimer's disease.

The Mediterranean diet includes high intake of vegetables, legumes, fruits, cereals, fish and monounsaturated fatty acids such as olive oil; low intake of saturated fatty acids, dairy products, meat and poultry; and mild to moderate amounts of alcohol.

And an 11-year study of over 3800 seniors found that those who adhered more closely to an anti-hypertension diet (DASH) maintained their cognitive performance better over time, and that this appeared due to intake of four food groups: vegetables, whole grains, low-fat dairy, nut/legumes.

Other studies have pointed to the importance of maintaining blood sugar levels.(These studies, with the exception of the Swedish study, are all ones that have been previously reported on this site.)

We can be fairly sure that fighting inflammation, hypertension, and so on, help us fend off cognitive decline and impairment in our senior years. We can also be reasonably sure that fruit and vegetables are good for us. No one’s arguing much about fish either (although you do have to consider the toxicity of the fish, especially mercury load). There’s a messy ground however over the whole carbohydrate, sugar, fat, protein, dairy ground.

Recently I read a very interesting article reviewing a new book called Good Calories, Bad Calories. In this book, the author apparently “dispels nearly every belief doctors and the public health community hold to be true about nutrition and health”. According to the blogger, “It would be easy to dismiss his claims, except that he makes his case not with theories and conjectures, but through a meticulous review of the nutrition and medical literature going back a hundred years.” Moreover, the claims do help explain some of the more puzzling quandaries about the rise of obesity.

They also, I have to say, fit in with my own experience.

The basic tenet of the book is that it is carbohydrates, and most especially refined carbohydrates, that are to blame for our current epidemics of obesity, diabetes, coronary heart disease, and even cancer. We should avoid anything made with flour, cereals, potatoes, and anything with a lot of sugar (bananas, I’m afraid, are also a no-no). We don’t, on the other hand, need to worry about meat, dairy, or fat.

This is, in fact, exactly what I have found in my own struggles with weight (although of course my reason for discussing this here is not weight per se but more fundamental physical problems). When my weight climbed to what I regarded as appalling levels, I lost the desired 20kg through a rigorous low-carbohydrate diet (although my reasons actually had more to do with trying to work through my food sensitivities). And when I say low-carbohydrate, I was actually living mainly on fruit and vegetables. I did find, after a while, that the lack of carbohydrate created an energy problem, but a quarter-cup (uncooked) of brown rice every day fixed that. When, after a couple of years, I loosened up on my diet, having some bread (gluten-free; yeast-free!), the occasional bit of baking, the occasional small bit of potato … well, my weight immediately started climbing again. I complain that I only have to look at some baking to add weight!

I’m fully conscious that this wouldn’t be everyone’s experience — I live with three males, all of whom are the tall, lean type, who can eat vast quantities of baking without it apparently having any effect. But this is my point. I think the author of this book makes some good points about the difficulties of diet research, and he may well be right in his recommendations. But even when we get to the point when we can be certain of what is a “healthy diet”, it’s still not going to be true for everyone.

So my advice to individuals is that you don’t take the disputes among health and nutrition experts as an excuse for eating what you like, but instead as a basis for exploration. Look at the various diets for which there is some evidence, and work out which ones work for you. Which will depend not only on your genetic makeup, but most particularly on the damage you’ve already done to your body (not pointing a finger! We’ve all damaged our bodies just by living). As a reminder of which I was interested to read  an interesting article in the New York Times on the high-fat diet recommended for  epileptics. 

Even mild head injuries can seriously affect the brain

Traumatic brain injury is the biggest killer of young adults and children in the U.S., and in a year more Americans suffer a TBI than are diagnosed with breast, lung, prostate, brain and colon cancer combined. There are many causes of TBI, but one of the more preventable is that of sports concussion.

This week Pennsylvania became the 35th state in the U.S. to have a youth-concussion law. Since I recently uploaded a topic collection on TBI (traumatic brain injury), this seems an appropriate time to talk a little about sports concussions and their possible long-time repercussions.

In 2009, a study commissioned by the National Football League reported that Alzheimer’s disease or similar memory-related diseases had been diagnosed in the league’s former players dramatically more often than in the national population: five times the national average among those 50 and older (6.1%) and 19 times for those aged 30 through 49.

This follows a 2005 study that found retired National Football League players had a 37% higher risk of Alzheimer's than other U.S. males of the same age. Those who had experienced three or more concussions had a five-fold greater chance of having been diagnosed with mild cognitive impairment and a three-fold prevalence of reported significant memory problems compared to those players without a history of concussion.

Most recently, a follow-up of nearly 4,000 retired National Football League players surveyed in 2001 found that 35% appeared to have significant cognitive problems. When 41 of them were tested, they were found to have mild cognitive impairment that resembled a comparison group of much older patients from the general population.

Now, you might (if you’re a parent) console yourself with the thought that professional football players are likely to be involved in much greater impacts than those suffered by your child on the sport’s field. But unfortunately there is growing evidence that even mild concussions can produce long-lasting trauma to the brain.

For example, monitoring of 11 high school football players found that some players who hadn't been diagnosed with concussions nevertheless had developed changes in brain function following head impacts, and these changes correlated with cognitive impairment. Brain scans have also revealed abnormalities in white matter at all levels of severity in traumatic brain injury, even in those who had minimal or no loss of consciousness, and those with no self-reported cognitive deficit. And analysis of medical records on over 280,000 older U.S. military veterans found that severity of brain injury made no difference to the increased likelihood that they would develop dementia.

Not all impacts are equally bad. There’s some evidence that the area to the top and front of the head (just above the dorsolateral prefrontal cortex) is particularly vulnerable.

Another danger sign is headaches. A study found that young athletes who experienced migraine headache symptoms (even one week after concussion) were likely to have increased cognitive impairment, and shouldn’t return to play before the headache resolves.

Children exposed to lead early in life might also be especially vulnerable to the effects of head injury. Rat studies have found that young rats exposed to low levels of lead don’t recover from brain injury as well as those not so exposed.

Head trauma shouldn’t be accepted fatalistically. There are actions you can take to ameliorate its effects (if you don’t want to remove yourself from the risky situations). What these findings emphasize is the importance of treating even mild head injuries, of giving your brain time to repair itself, and of following a regime designed to mitigate damage: exercising, eating a healthy diet, reducing stress, and so on.

My recent report on transient global amnesia demonstrates the incredible ability of the brain to repair itself — but it must be given time to do so before subjecting it to more trauma. According to a leading tracker of youth sports injuries, returning to play too soon is a trend that occurs in roughly 40% of sports-related concussions of student football players.

The three main provisions of Washington state's Zackery Lystedt law, considered by the National Football League to be model youth-concussion legislation, are:

  • a student-athlete's parent or guardian must sign a concussion-awareness information form before the student-athlete is eligible to participate in school athletics;
  • any student-athlete suspected of a concussion must immediately be removed from play;
  • any student-athlete who has a concussion must obtain medical clearance before being allowed to return to practice or competition.

Many states also require some form of concussion training for coaches.


References (and more details) for the studies I have mentioned can be found in my topic collection on TBI.

Diabetes - its role in cognitive impairment & dementia

There was an alarming article recently in the Guardian newspaper. It said that in the UK, diabetes is now nearly four times as common as all forms of cancer combined. Some 3.6 million people in the UK are thought to have type 2 diabetes (2.8 are diagnosed, but there’s thought to be a large number undiagnosed) and nearly twice as many people are at high risk of developing it. The bit that really stunned me? Diabetes costs the health service roughly 10% of its entire budget. In north America, one in five men over 50 have diabetes. In some parts of the world, it’s said as much as a quarter of the population have diabetes or even a third (Nauru)! Type 2 diabetes is six times more common in people of South Asian descent, and three times in people of African and African-Caribbean origin.

Why am I talking about diabetes in a blog dedicated to memory and learning? Because diabetes, if left untreated, has a number of complications, several of which impinge on brain function.

For example, over half of those with type 2 diabetes will die of cardiovascular disease, and vascular risk factors not only increase your chances of heart problems and stroke (diabetes doubles your risk of stroke), but also of cognitive impairment and dementia.

Type 2 diabetes is associated with obesity, which can bring about high blood pressure and sleep apnea, both of which are cognitive risk factors.

Both diabetes and hypertension increases the chances of white-matter lesions in the brain (this was even evident in obese adolescents with diabetes), and the degree of white-matter lesions in the brain is related to the severity of age-related cognitive decline and increased risk of Alzheimer’s.

Mild cognitive impairment is more likely to develop into Alzheimer’s if vascular risk factors such as high blood pressure, diabetes, cerebrovascular disease and high cholesterol are present, especially if untreated. Indeed it has been suggested that Alzheimer’s memory loss could be due to a third form of diabetes. And Down syndrome, Alzheimer's, diabetes, and cardiovascular disease, have been shown to share a common disease mechanism.

So diabetes is part of a suite of factors that act on the heart and the brain.

But treatment of such risk factors (e.g. by using high blood pressure medicines, insulin, cholesterol-lowering drugs and diet control, giving up smoking or drinking) significantly reduces the risk of developing Alzheimer’s. Bariatric surgery has been found to improve cognition in obese patients. And several factors have been shown to make a significant difference as to whether a diabetic develops cognitive problems.

Older diabetics are more likely to develop cognitive problems if they:

  • have higher (though still normal) blood pressure,
  • have gait and balance problems,
  • report themselves to be in bad health regardless of actual problems (this may be related to stress and anxiety),
  • have higher levels of the stress hormone cortisol,
  • don’t manage their condition (poor glucose control),
  • have depression,
  • eat high-fat meals.

Glucose control / insulin sensitivity may be a crucial factor even for non-diabetics. A study involving non-diabetic middle-aged and elderly people found that those with impaired glucose tolerance (a pre-diabetic condition) had a smaller hippocampus and scored worse on tests for recent memory. And some evidence suggests that a link found between midlife obesity and increased risk of cognitive impairment and dementia in old age may have to do with poorer insulin sensitivity.

Exercise and dietary changes are of course the main lifestyle factors that can turn such glucose impairment around, and do wonders for diabetes too. In fact, a recent small study found that an extreme low-calorie diet (don’t try this without medical help!) normalized pre-breakfast blood sugar levels and pancreas activity within a week, and may even have permanently cured some diabetics after a couple of months.

Diabetes appears to affect two cognitive domains in particular: executive functioning and speed of processing.

You can read all the research reports on diabetes that I’ve made over the years in my new topic collection.

Neglect your senses at your cognitive peril!

Impaired vision is common in old age and even more so in Alzheimer’s disease, and this results not only from damage in the association areas of the brain but also from problems in lower-level areas. A major factor in whether visual impairment impacts everyday function is contrast sensitivity.

Contrast sensitivity not only slows down your perceiving and encoding, it also interacts with higher-order processing, such as decision-making. These effects may be behind the established interactions between age, perceptual ability, and cognitive ability. Such interactions are not restricted to sight — they’ve been reported for several senses.

In fact, it’s been suggested that much of what we regard as ‘normal’ cognitive decline in aging is simply a consequence of having senses that don’t work as well as they used to.

The effects in Alzheimer’s disease are, I think, particularly interesting, because we tend to regard any cognitive impairment here as inevitable and a product of pathological brain damage we can’t do anything much about. But what if some of the cognitive impairment could be removed, simply by improving the perceptual input?

That’s what some recent studies have shown, and I think it’s noteworthy not only because of what it means for those with Alzheimer’s and mild cognitive impairment, but also because of the implications for any normally aging person.

So let’s look at some of this research.

Let’s start with the connection between visual and cognitive impairment.

Analysis of data from the Health and Retirement Study and Medicare files, involving 625 older adults, found that those with very good or excellent vision at baseline had a 63% reduced risk of developing dementia over a mean follow-up period of 8.5 years. Those with poorer vision who didn’t visit an ophthalmologist had a 9.5-fold increased risk of Alzheimer disease and a 5-fold increased risk of mild cognitive impairment. Poorer vision without a previous eye procedure increased the risk of Alzheimer’s 5-fold. For Americans aged 90 years or older, 78% who kept their cognitive skills had received at least one previous eye procedure compared with 52% of those with Alzheimer’s disease.

In other words, if you leave poor vision untreated, you greatly increase your risk of cognitive impairment and dementia.

Similarly, cognitive testing of nearly 3000 older adults with age-related macular degeneration found that cognitive function declined with increased macular abnormalities and reduced visual acuity. This remained true after factors such as age, education, smoking status, diabetes, hypertension, and depression, were accounted for.

And a study comparing the performance of 135 patients with probable Alzheimer’s and 97 matched normal controls on a test of perceptual organization ability (Hooper Visual Organization Test) found that the VOT was sensitive to severity of dementia in the Alzheimer’s patients.

So let’s move on to what we can do about it. Treatment for impaired vision is of course one necessary aspect, but there is also the matter of trying to improve the perceptual environment. Let’s look at this research in a bit more detail.

A 2007 study compared the performance of 35 older adults with probable Alzheimer’s, 35 healthy older adults, and 58 young adults. They were all screened to exclude those with visual disorders, such as cataracts, glaucoma, or macular degeneration. There were significant visual acuity differences between all 3 groups (median scores: 20/16 for young adults; 20/25 for healthy older adults; 20/32 for Alzheimer’s patients).

Contrast sensitivity was also significantly different between the groups, although this was moderated by spatial frequency (normal contrast sensitivity varies according to spatial frequency, so this is not unexpected). Also unsurprisingly, the young adults outperformed both older groups at every spatial frequency, except at the lowest, where it was matched by that of healthy older adults. Similarly, healthy older adults outperformed Alzheimer’s patients at every frequency bar one — the highest frequency.

For Alzheimer’s patients, there was a significant correlation between contrast sensitivity and their cognitive (MMSE) score (except at the lowest frequency of course).

Participants carried out a number of cognitive/perceptual tasks: letter identification; word reading; unfamiliar-face matching; picture naming; pattern completion. Stimuli varied in their perceptual strength (contrast with background).

Letter reading: there were no significant differences between groups in terms of accuracy, but stimulus strength affected reaction time for all participants, and this was different for the groups. In particular, older adults benefited most from having the greatest contrast, with the Alzheimer’s group benefiting more than the healthy older group. Moreover, Alzheimer’s patients seeing the letters at medium strength were not significantly different from healthy older adults seeing the letters at low strength.

Word reading: here there were significant differences between all groups in accuracy as well as reaction time. There was also a significant effect of stimulus strength, which again interacted with group. While young adults’ accuracy wasn’t affected by stimulus strength, both older groups were. Again, there were no differences between the Alzheimer’s group and healthy older adults when the former group was at high stimulus strength and the latter at medium, or at medium vs low. That was true for both accuracy and reaction time.

Picture naming: By and large all groups, even the Alzheimer’s one, found this task easy. Nevertheless, there were effects of stimulus strength, and once again, the performance of the Alzheimer’s group when the stimuli were at medium strength matched that of healthy older adults with low strength stimuli.

Raven’s Matrices and Benton Faces: Here the differences between all groups could not in general be ameliorated by manipulating stimulus strength. The exception was with the Benton Faces, where Alzheimer’s patients seeing the medium strength stimuli matched the performance of healthy older adults seeing low strength stimuli.

In summary, then, for letter reading (reaction time), word reading (identification accuracy and reaction time), picture naming, and face discrimination, manipulating stimulus strength in terms of contrast was sufficient to bring the performance of individuals with Alzheimer’s to a level equal to that of their healthy age-matched counterparts.

It may be that the failure of this manipulation to affect performance on the Raven’s Matrices reflects the greater complexity of these stimuli or the greater demands of the task. However, the success of the manipulation in the case of the Benton Faces — a similar task with stimuli of apparently similar complexity — contradicts this. It may that the stimulus manipulation simply requires some more appropriate tweaking to be effective.

It might be thought that these effects are a simple product of making stimuli easier to see, but the findings are a little more complex than I’ve rendered them. The precise effect of the manipulation varied depending on the type of stimuli. For example, in some cases there was no difference between low and medium stimuli, in others no difference between medium and high; in some, the low contrast stimuli were the most difficult, in others the low and medium strength stimuli were equally difficult, and on one occasion high strength stimuli were more difficult than medium.

The finding that Alzheimer’s individuals can perform as well as healthy older adults on letter and word reading tasks when the contrast is raised suggests that the reading difficulties that are common in Alzheimer’s are not solely due to cognitive impairment, but are partly perceptual. Similarly, naming errors may not be solely due to semantic processing problems, but also to perceptual problems.

Alzheimer’s individuals have been shown to do better recognizing stimuli the closer the representation is to the real-world object. Perhaps it is this that underlies the effect of stimulus strength — the representation of the stimulus when presented at a lower strength is too weak for the compromised Alzheimer’s visual system.

All this is not to say that there are not very real semantic and cognitive problems! But they are not the sole issue.

I said before that for Alzheimer’s patients there was a significant correlation between contrast sensitivity and their MMSE score. This is consistent with several studies, which have found that dementia severity is correlated with contrast sensitivity at some spatial frequencies. This, and these experimental findings, suggests that contrast sensitivity is in itself an important variable in cognitive performance, and contrast sensitivity and dementia severity have a common substrate.

It’s also important to note that the manipulations of contrast were standard across the group. It may well be that individualized manipulations would have even greater benefits.

Another recent study comparing the performance of healthy older and younger adults and individuals with Alzheimer's disease and Parkinson's disease on the digit cancellation test (a visual search task used in the diagnosis of Alzheimer’s), found that increased contrast brought the healthy older adults and those with Parkinson’s up to the level of the younger adults, and significantly benefited Alzheimer’s individuals — without, however, overcoming all their impairment.

There were two healthy older adults control groups: one age-matched to the Alzheimer’s group, and one age-matched to the Parkinson’s group. The former were some 10.5 years older to the latter. Interestingly, the younger control group (average age 64) performed at the same level as the young adults (average age 20), while the older old control group performed significantly worse. As expected, both the Parkinson’s group and the Alzheimer’s group performed worse than their age-matched controls.

However, when contrast was individually tailored at the level at which the person correctly identified a digit appearing for 35.5 ms 80% of the time, there were no significant performance differences between any of the three control groups or the Parkinson’s group. Only the Alzheimer’s group still showed impaired performance.

The idea of this “critical contrast” comparison was to produce stimuli that would be equally challenging for all participants. It was not about finding the optimal level for each individual (and indeed, young controls and the younger old controls both performed better at higher contrast levels). The findings indicate that poorer performance by older adults and those with Parkinson’s is due largely to their weaker contrast sensitivity, but those with Alzheimer’s are also hampered by their impaired ability to conduct a visual search.

The same researchers demonstrated this in a real-world setting, using Bingo cards. Bingo is a popular activity in nursing homes, senior centers and assisted-living facilities, and has both social and cognitive benefits.

Varying cards in terms of contrast, size, and visual complexity found that all groups benefited from increasing stimulus size and decreasing complexity. Those with mild Alzheimer’s were able to perform at levels comparable to their healthy peers, although those with more severe dementia gained little benefit.

Contrast boosting has also been shown to work in everyday environments: people with dementia can navigate more safely around their homes when objects in it have more contrast (e.g. a black sofa in a white room), and eat more if they use a white plate and tableware on a dark tablecloth or are served food that contrasts the color of the plate.

There’s a third possible approach that might also be employed to some benefit, although this is more speculative. A study recently reported at the American Association for the Advancement of Science annual conference revealed that visual deficits found in individuals born with cataracts in both eyes who have had their vision corrected can be overcome through video game playing.

After playing an action video game for just 40 hours over four weeks, the patients were better at seeing small print, the direction of moving dots, and the identity of faces.

The small study (this is not, after all, a common condition) involved six people aged 19 to 31 who were born with dense cataracts in each eye. Despite these cataracts being removed early in life, such individuals still grow up with poorer vision, because normal development of the visual cortex has been disrupted.

The game required players to respond to action directly ahead of them and in the periphery of their vision, and to track objects that are sometimes faint and moving in different directions. Best results were achieved when players were engaged at the highest skill level they could manage.

Now this is quite a different circumstance to that of individuals whose visual system developed normally but is now degrading. However, if vision worsens for some time before being corrected, or if relevant activities/stimulation have been allowed to decline, it may be that some of the deficit is not due to damage as such, but more malleable effects. In the same way that we now say that cognitive abilities need to be kept in use if they are not to be lost, perceptual abilities (to the extent that they are cognitive, which is a great extent) may benefit from active use and training.

In other words, if you have perceptual deficits, whether in sight, hearing, smell, or taste, you should give some thought to dealing with them. While I don’t know of any research to do with taste, I have reported on several studies associating hearing loss with age-related cognitive impairment or dementia, and similarly olfactory impairment. Of particular interest is the research on reviving a failing sense of smell through training, which suggested that one road to olfactory impairment is through neglect, and that this could be restored through training (in an animal model). Similarly, I have reported, more than once, on the evidence that music training can help protect against hearing loss in old age. (You can find more research on perception, training, and old age, on the Perception aggregated news page.)


For more on the:

Bingo study:

Video game study:


(In order of mention)

Rogers MA, Langa KM. 2010. Untreated poor vision: a contributing factor to late-life dementia. American Journal of Epidemiology, 171(6), 728-35.

Clemons TE, Rankin MW, McBee WL, Age-Related Eye Disease Study Research Group. 2006. Cognitive impairment in the Age-Related Eye Disease Study: AREDS report no. 16. Archives of Ophthalmology, 124(4), 537-43.

Paxton JL, Peavy GM, Jenkins C, Rice VA, Heindel WC, Salmon DP. 2007. Deterioration of visual-perceptual organization ability in Alzheimer's disease. Cortex, 43(7), 967-75.

Cronin-Golomb, A., Gilmore, G. C., Neargarder, S., Morrison, S. R., & Laudate, T. M. (2007). Enhanced stimulus strength improves visual cognition in aging and Alzheimer’s disease. Cortex, 43, 952-966.

Toner, Chelsea K.;Reese, Bruce E.;Neargarder, Sandy;Riedel, Tatiana M.;Gilmore, Grover C.;Cronin-Golomb, A. 2011. Vision-fair neuropsychological assessment in normal aging, Parkinson's disease and Alzheimer's disease. Psychology and Aging, Published online December 26.

Laudate, T. M., Neargarder S., Dunne T. E., Sullivan K. D., Joshi P., Gilmore G. C., et al. (2011). Bingo! Externally supported performance intervention for deficient visual search in normal aging, Parkinson's disease, and Alzheimer's disease. Aging, Neuropsychology, and Cognition. 19(1-2), 102 - 121.

Aging successfully

In a recent news report, I talked about a study of older adults that found that their sense of control over their lives fluctuates significantly over the course of a day, and that this impacts on their cognitive abilities, including reasoning and memory. ‘Sense of control’ — a person’s feeling that they are (or are not) in control of their life — is an attribute that includes perceived competence, as well as locus of control, and in general it tends to decline in older adults. But obviously it is an attribute that, across the board, varies dramatically between individuals.

In older adults, a stronger sense of control is associated with more successful aging, and among people in general, with better cognitive performance. This isn’t surprising, as it is entirely consistent with related associations we have found: between strategy use and cognitive performance; between the belief that intelligence is malleable rather than fixed and cognitive performance.

My point here, however, is the connection between these findings and other aspects of successful aging that impact mental performance.

For example, I have spoken before about the association between age-related hearing loss and cognitive impairment (see this recent New York Times blog post for a very nice report on this), and poor vision and cognitive impairment.

Similarly, high blood pressure, diabetes, and depression have all been implicated in age-related cognitive decline and dementia. (For more on these, see the topic collection on diabetes, the topic collection on depression, and the new topic collection on hypertension.)

Depression, and poorer hearing and vision, are aspects of health and well-being that many seniors ignore, regarding them as no more than can be expected in old age. But their occurrence, however inevitable that may be, should not be regarded as untreatable, and seniors and their loved ones (and any with a duty of care) should be aware that by letting them go untreated, the consequences may well be more serious than they imagine.

Hypertension and diabetes, too, are medical problems that often go untreated. These problems often begin in middle age, and again, people are often unaware that their procrastination or denial may have serious implications further down the line. There is growing evidence that the roots of cognitive decline and dementia lie in your lifestyle over your lifetime, and in middle age especially.

Similarly, chronic stress may not only impair your mental performance at the time, but have long-term implications for your mental health in later old age. It is therefore an important problem to recognize and do something about for long-term health as well as present happiness. Scientific American has a self-assessment tool to help you recognize how much stress you are experiencing.

What does all this have to do with the sense of control association? Well, it seems to me that people who feel in control of their lives will be more likely to take action to deal with any of these problems; those who don’t feel in control of their lives will tend not to take such action. Thus giving up their control, and making their beliefs about the perils of aging a self-fulfilling prophecy.

A final note: my talk of treatment should not be taken as advocating a medicalized view of aging. Another aspect of aging and cognition is the widespread use of drugs among older adults. In the U.S., it’s reported that over 40% of those over 65 take five or more medications, and each year about one-third of them experience a serious adverse effect. You can read more about this in this New York Times blog article.

Hypertension, diabetes, depression, and stress are all problems that are amenable to a range of treatments, of which I personally would put drugs last.

But my point here is not to advocate specific treatments! I am a cognitive psychologist, not a medical doctor. All I wish to do in this post is provide a warning and some resources.